Fuel return line filter?
04-22-2018, 01:37 PM
#1
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Fuel return line filter?
I have gas leak that is coming from what looks like a filter plumbed into the fuel return line. I look thru the manual and couldn’t find any references to it. It's bolted down right above the fuel feed filter.
1987 coupe. Anybody run into this before?
1987 coupe. Anybody run into this before?
04-22-2018, 02:08 PM
#2
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Found an old thread from 2010 that referenced it. The inline return fuel filter was a 1987 only item.
04-22-2018, 03:37 PM
#3
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Actually, the 87 "return line filter" was not factory-installed, but was installed on some 87's as directed by a TSB that addressed customer complaints about a "knocking sound" when engine was cold.
The noise was a result of fuel-hammering (caused by the batch-fire injection of the L98) in the fuel lines being transmitted into the frame. The filter was installed to act as an accumulator to dampen the hammering pulses, and eliminate the noise.
My 85 has done it since new when cold, while letting the clutch out. The noise ceases within 1 minute of start-up. It never bothered me much, and I had no idea what it was until I found the TSB awhile back while researching the presence of the filter on an 87 at a NCRS Regional, but had never seen one on other 87's. In NCRS, the presence of the filter IS a deduction, because it is not factory-installed, nor is it safety-related.
The noise was a result of fuel-hammering (caused by the batch-fire injection of the L98) in the fuel lines being transmitted into the frame. The filter was installed to act as an accumulator to dampen the hammering pulses, and eliminate the noise.
My 85 has done it since new when cold, while letting the clutch out. The noise ceases within 1 minute of start-up. It never bothered me much, and I had no idea what it was until I found the TSB awhile back while researching the presence of the filter on an 87 at a NCRS Regional, but had never seen one on other 87's. In NCRS, the presence of the filter IS a deduction, because it is not factory-installed, nor is it safety-related.
04-22-2018, 07:44 PM
#4
Actually, the 87 "return line filter" was not factory-installed, but was installed on some 87's as directed by a TSB that addressed customer complaints about a "knocking sound" when engine was cold.
The noise was a result of fuel-hammering (caused by the batch-fire injection of the L98) in the fuel lines being transmitted into the frame. The filter was installed to act as an accumulator to dampen the hammering pulses, and eliminate the noise.
My 85 has done it since new when cold, while letting the clutch out. The noise ceases within 1 minute of start-up. It never bothered me much, and I had no idea what it was until I found the TSB awhile back while researching the presence of the filter on an 87 at a NCRS Regional, but had never seen one on other 87's. In NCRS, the presence of the filter IS a deduction, because it is not factory-installed, nor is it safety-related.
The noise was a result of fuel-hammering (caused by the batch-fire injection of the L98) in the fuel lines being transmitted into the frame. The filter was installed to act as an accumulator to dampen the hammering pulses, and eliminate the noise.
My 85 has done it since new when cold, while letting the clutch out. The noise ceases within 1 minute of start-up. It never bothered me much, and I had no idea what it was until I found the TSB awhile back while researching the presence of the filter on an 87 at a NCRS Regional, but had never seen one on other 87's. In NCRS, the presence of the filter IS a deduction, because it is not factory-installed, nor is it safety-related.
I don't know how the conversation ended but the TSB was for '85 and '86 cars and was a "KIT". The TSB was 86-234 and that's been posted many times I believe.
'87 the 'return filter' was thought to be production and possibly very late '87 cars got the 'accumulator' that was used in '88. The front return line for '87 were part#'d differently and only a single year. That's pretty well documented. Filter assembly and element were in SPO publications as '87. TSB related 'service parts' aren't published.
Here's the TSB: http://www.quayle-co.com/tsbs/86-234.htm
This is a very interesting document from an NCRS "Chapter" where it was mentioned but nothing mentioned regarding the 'accumulator' being added to end of production '87 cars. See page 6.
http://www.arizonancrs.com/resources...-june-2008.pdf
This has never been of any interest to me because I don't own an '87 but for those that do it could be interesting research for sure. It would be interesting to see some very late '87 fuel lines to see if the accumulator is actually there.